package Demo2;
abstract class Shape{
    public abstract void draw1();    //抽象方法abstract，类也要加上
    public abstract void draw2();
    public abstract void draw3();

}
class A extends Shape{

    @Override
    public void draw1() {

    }

    @Override
    public void draw2() {

    }

    @Override
    public void draw3() {

    }
}

public class Test {
}
